diff --git a/ssl/d1_clnt.c b/ssl/d1_clnt.c
index d8cf92686..0fea8659a 100644
--- a/ssl/d1_clnt.c
+++ b/ssl/d1_clnt.c
@@ -1548,6 +1548,12 @@ int dtls1_send_client_certificate(SSL *s)
 		s->state=SSL3_ST_CW_CERT_D;
 		l=dtls1_output_cert_chain(s,
 			(s->s3->tmp.cert_req == 2)?NULL:s->cert->key->x509);
+		if (!l)
+			{
+			SSLerr(SSL_F_DTLS1_SEND_CLIENT_CERTIFICATE, ERR_R_INTERNAL_ERROR);
+			ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_INTERNAL_ERROR);
+			return 0;
+			}
 		s->init_num=(int)l;
 		s->init_off=0;
 
diff --git a/ssl/d1_srvr.c b/ssl/d1_srvr.c
index a14fb4313..f52c735a5 100644
--- a/ssl/d1_srvr.c
+++ b/ssl/d1_srvr.c
@@ -1446,6 +1446,11 @@ int dtls1_send_server_certificate(SSL *s)
 			}
 
 		l=dtls1_output_cert_chain(s,x);
+		if (!l)
+			{
+			SSLerr(SSL_F_DTLS1_SEND_SERVER_CERTIFICATE,ERR_R_INTERNAL_ERROR);
+			return(0);
+			}
 		s->state=SSL3_ST_SW_CERT_B;
 		s->init_num=(int)l;
 		s->init_off=0;